Re: [PATCH 3/5] trace-cmd: Use errno from zlib, if available

From: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
To: "Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com>
Cc: rostedt@goodmis.org, linux-trace-devel@vger.kernel.org
Subject: Re: [PATCH 3/5] trace-cmd: Use errno from zlib, if available
Date: Wed, 2 Mar 2022 08:15:30 +0100	[thread overview]
Message-ID: <Yh8Zkh7nQhLZnpsU@breakpoint.cc> (raw)
In-Reply-To: <20220302045131.387658-4-tz.stoyanov@gmail.com>

On 2022-03-02 06:51:29 [+0200], Tzvetomir Stoyanov (VMware) wrote:
> Some zlib APIs set the errno in case of an error and return Z_ERRNO.
> In these cases, errno should not be overwritten by the tarce-cmd zlib
> wrappers.
> 
> Suggested-by: Sebastian Andrzej Siewior <sebastian@breakpoint.cc>
> Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
> ---
>  lib/trace-cmd/trace-compress-zlib.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/lib/trace-cmd/trace-compress-zlib.c b/lib/trace-cmd/trace-compress-zlib.c
> index 41342597..0dfd4f15 100644
> --- a/lib/trace-cmd/trace-compress-zlib.c
> +++ b/lib/trace-cmd/trace-compress-zlib.c
> @@ -33,6 +33,8 @@ static int zlib_compress(const void *in, int in_bytes, void *out, int out_bytes)
>  	case Z_STREAM_ERROR:
>  		errno = -EINVAL;
>  		break;
> +	case Z_ERRNO:
> +		break;
>  	default:
>  		errno = -EFAULT;
>  		break;
> @@ -61,6 +63,8 @@ static int zlib_decompress(const void *in, int in_bytes, void *out, int out_byte
>  	case Z_DATA_ERROR:
>  		errno = -EINVAL;
>  		break;
> +	case Z_ERRNO:
> +		break;
>  	default:
>  		errno = -EFAULT;
>  		break;

I was thinking about returning the error for compress/decompress via the
return value and not touching errno at all.

Sebastian